Ediacaran skeletal metazoan interpreted as a lophophorate

Andrey Yu Zhuravlev, Rachel Wood

Research output: Contribution to journalArticlepeer-review

Abstract

While many skeletal biomineralised genera are described from Ediacaran (635-541 million years ago; Ma) strata, none have been suggested to have an affinity above the Porifera-Cnidaria metazoan grade. Here we reinterpret the widespread terminal Ediacaran (~550-541 Ma) sessile goblet-shaped Namacalathus as a triploblastic eumetazoan. Namacalathus has a stalked cup with radially-symetrical cross section, multiple lateral lumens, and a central opening. We show that the skeleton of Namacalathus is composed of a calcareous foliated ultrastructure displaying regular concordant columnar inflections, with a possible inner organic-rich layer. These features point to an accretionary growth style of the skeleton and an affinity with the Lophotrochozoa, more specifically within the Lophophorata (Brachiopoda and Bryozoa). Additionally, we present evidence for asexual reproduction as expressed by regular budding in a bilateral pattern.
The interpretation of Namacalathus as an Ediacaran total group lophophorate is consistent with an early radiation of the Lophophorata, as known early Cambrian representatives were sessile, mostly stalked forms, and in addition the oldest known calcareous Brachiopoda (early Cambrian Obolellida) and Bryozoa (Ordovician Stenolaemata) possessed foliated ultrastructures.
Original languageEnglish
Pages (from-to)1-22
Number of pages22
JournalProceedings of the Royal Society B-Biological Sciences
Volume282
Issue number1818
DOIs
Publication statusPublished - 4 Nov 2015

Keywords

  • Ediacaran
  • Lophophorate
  • Bilateria
  • Metazoan

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